statistics
posted by kelly .
the mean scale score on the mathematics examination of ninth grade students in new york state was 86 with a standard deviation of 5 points. Given a student was selected at random what is the probabilty that his score was 91 or higher?

statistics 
PsyDAG
Z = (scoremean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.
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